Refrigerating apparatus



g- '1944- D. F. ALEXANDER EIAL. 2,355,040

REFRI GERAT ING APPARATUS Filed July 30, 1941 6 Sheets-Sheet 1 PatentedAug 8, 1944 UNI D STATES PATENT OFFICE nnrmonaa'rmo' APPARATUS -DonaldF. Alexander, Oakwood and James R. Hornaday and Albert J. Kuhn, Dayton,Ohio, assignors to General Motors Corporation, Dayton, Ohio, acorporation of Delaware Application July 30, 1941, Serial No. 404,686

6 Claims. (Cl. 257--3) This invention relates to refrigerating apparatusand more particularly to an improved arrangement for conditioning theair in a railway car or the like.

It is common practicein air conditioning systems to utilize waste heatof a prime mover for supplying heat to an enclosure for heating It hasbeen found, however, that nupurposes. merous problems are involved incontrolling the discharge of this waste heat into the conditioned space.It is an object of this invention to provide an improved control systemfor determining when and where this waste heat is to be disvide animproved arrangement for changing from overhead heating to floorheating.

A further object of this invention is to provide a simplifiedarrangement for selecting the tem-. perature to be maintained withinaconditioned space.

Another object is to provide an improved control for controlling theheating of the car while standing in the yard. I

Further objects and advantages of the present invention will be apparentfromthe following description, reference being had to the accompanyingdrawings, wherein a preferred form of the present invention is,elearlyshown.

In the drawings:

Fig. 1 diagrammatically shows a preferred arrangement of the heating andcooling elements as applied to a railway car;

Fig. 2 shows an electrical circuit which may be used in controlling theheating and cooling apparatus shown in Fig. 1;

Figs. 3 and 4 correspond to Fig. 2 and show which portions of the maincircuit are energized under certain designated temperatures; and

Figs. 5 and 6 show a modified form of control circuit.

Reference numeral l0 designates a conventional railway car of thepassenger type equipped with air conditioning apparatus embodying ourinvention. Reference numeral 12 designates a conventional refrigerantevaporator which is used for cooling the air for the passengercompartment during the summer season. -The compressor l4 withdrawsvaporized refrigerant from the evaporator I2 and discharges compressedrefrigerant into the condenser IS in accordance with well-knownpractice. The condensed reit t has l n Common Practice to utilize.-

frigerant is supplied to, the evaporator through the line l8 in which islocated a conventional refrigerant flow control device 20. The control20 may be either of the thermostatic expansion valve type or the fixedrestrictor type. The air to be conditioned is circulated over theevaporator l2 by means of the fan unit 22.

A separate fan unit 24 has been provided for ventilating purposes soas'to provide circulation of either fresh air, return air or a mixtureof both. The fan unit 24 draws fresh air into-the car through the dampercontrolled inlet 26 and recirculates car air through the opening 21.This fan unit may operate simultaneously with the fan unit 22 or it maybe used to operate at suchtimes when fan unit 22 is not in operation.

Reference numeral 30 designates an internal combustion engine preferablyof the Diesel type which is'used for supplying power for driving thegenerator 32. The generator 32 may be either a direct current generatoror an .altenating cur rent generator and is used for supplyingelectrical energy to the electric floor heaters 34 mounted in thepassenger compartment 23 of the vehicle Ill. The generator 32 alsosupplies electric energy to the compressor operating motor 36. A doublepole switch 38 is provided for dis-.-

connecting the compressor motor 36 and the floor heaters 34 from thegenerator 32.

Since there may be times when either refrigeration or heating may berequired when the Diesel engine 30 is not in operation, such as when thevehicle is standing at a station, means have been provided for supplyingoutside electrical energy to the floor heaters 34 or the compressormotor 36. This means comprises a plug 40 which may be plugged into thesocket 42 carried by the car. The plug 40 is provided with leads 44connected to an external source of electrical energy at the station. Ajumper 46 is provided on the plug 40 for bridging the contacts 48 for apurpose to be explained more fully hereinafter. In order to simplify thedisclosure we have shown the switch 38 as a manually controlled switch,whereas in actual practice this switch would be controlledautomatically, so as to open upon the electrical circuit being connectedto the outside source of current. The flow of current to the electricfloor heaters 34. is controlled by the solenoid operated switch 50, asexplained more fully hereinafter. Likewise the flow of current to thecompressor motor 38' is controlled by the solenoid operated switch 52,as explained more fully hereinafter.

the waste heat of an internal combustion engine for heating the air foran enclosure during the winter. The waste heat of an engine has alsobeen used for reheating the air during the summer season. In the priorart systems, however, considerable difficulty has been experienced inproperly controlling the disposal of the waste heat of the engine.

In the arrangement shown in Fig. 1 the engine cooling 'fluid iscirculated by means of a conventional pump 54 driven by the engine 30 inac-* cordance with conventional practice. For convenience in descriptiononly, the engine cooling fluid willbe referred to hereinafter as water,whereas in actual practice an anti-freeze solution is used the yeararound so as to prevent the fluid from freezing.

A thermostatically controlled three-way valve 56 is provided forregulating the engine water temperature. The engine temperatureresponsive thermostat 58 controls the valve 56. Upon starting the enginethe three-way valve 56 causes all of the water discharged from theengine cooling jacket to flow directly through the line 60 to the intakeof the pump 54, whereby no water is circulated to any of the heatdissipating radiators until the engine temperature comes up to thattemperature at which the engine is designed to operate most efliciently.After the engine temperature comes up to normal the heated water leavingthe engine normally flows through the line 62 which leads to the lines64 and 66. The line 64 conveys the heater water to the overhead airheating coil 68 located at the air outlet side of the evaporator coil I2and the floor heating coil I2.

During cold weather heating is often required adjacent the floor of thepassenger compartment even though the temperature prevailing in theupper portion of the car is satisfactory. This is especially true when acar door is open since at that time cold air sweeps along the floor ofthe car. In order to simplify this disclosure, only one floor heatingcoil 12 has been shown whereas in actual practice several such coils areplaced.

along the length of the passenger compartment.

A group of valves controls the flow and thepath of the heater waterdelivered through line 64, passing this water through either one, orboth, of coils 68 and I2, or shutting ofi the flow entirely. Whenoverhead heat is not desired, but floor heat is desired, a by-pass Icontrolled by the valve V2 has been provided for supplying the heatedwater directly to floor heat coil 12. When overhead heat and floor heatare both required, water leaving the overhead heat coil 68 may besupplied to the coil 12 through the line 14 in which is provided controlvalve V3. When no floor heat is required but overhead heat in coil 68 isrequired for reheating during the summer season, the water leaving coil68 may be by-passed around the floor heat coil 12 through the by-passline I6 controlled by the valve V--4. The controls for operating valvesV-I, V-2, V3, V-l to accomplish the above functions are describedhereinafter.

Since there are times when no heating of any form is desired in thepassenger compartment, provision has been made for causing all of theheated water leaving the engine 30 to flow from the pipe 62 into thepipe 56 in which is'provided a valve V-I. When the valve V--I is open,all of the water flows directly to the main engine radiator 80 whichserves to cool the water in accordance with well-known practice. The fan82 which is driven by the main engine 30 circulates cooling air inthermal exchange with the radiator 80. The water leaving the radiator aswell as the water returning from the heating coils 58 and I2 flowsthrough the heat interchanger 04 through which the exhaust gas from theengine flows. The exhaust gas enters the heat interchanger 84 throughthe pipe 86 and is discharged through the pipe 80. A by-pass 90 has beenprovided in order to prevent overheating of the engine. The by-pass 90is controlled by the thermostatic valve 92 which in turn is controlledby a thermostatic bulb 9| placed in thermal exchange with the waterleaving the engine. The valve 92 opens when the temperature of the waterleaving the engine becomes excessive so as to cause water to flowdirectly into the main radiator 80 even though the valve VI is closed.

By providing the reheat coil 58 adiacentthe cooling coil I2 theapparatus may be used for dehumidifying the air when little or norefrigeration is required. During average operating conditions in thesummer time the refrigerating system will operate continuously and thetemperature within the passenger compartment will be controlled by theturning of! and on of the reheat. Under extreme conditions the coolingcapacity of the refrigerating system may be so great in comparison tothe capacity of the reheat coil that the reheat coil will operatecontinuously and the temperature will be controlled by turning on andoff the refrigerating system as will be explained more fullyhereinafter. As the outside temperature falls below the 50 value it isdesirable to completely discontinue the operation of the coolingapparatus and control the temperature in the passenger cgmpartment byturningon and oil the overhead heat and the floor heat.

Referring now to Figs. 2, 3 and 4, which show one form of electricalcircuit which may be used in controlling the heating and coolingapparatus shown in Figxl, reference numeral I00 designates aconventional storage battery which supplies electrical energy to thecontrol system. Reference numeral IOI designates a master control switchwhich is provided for deenergizing the entire circuit.

Since the temperature best suited for the passenger compartment willobviously vary from time to time depending largely upon the outside airtemperature, some means must be provided for adjusting the insidetemperature from time to time. The temperature to be maintained may beselected manually or automatically. Figs. 2, 3 and 4 show a circuitsuitable for use' when the inside temperature range is manually selectedwhereas Figs. 5 and 6 show a circuit which includes automatic selectionbased on the outside temperature. The controls which have been providedin each instance comprise the three overhead heat thermostats designatedby the reference numeral I03 in Figs. 2, 3 and 4, only one of which isintended to be placed in control at any one time, one 50 outsidethermostat I05 responsive to the outside air temperature, three coolingthermostats I01, only one of which is intended to be in control at anyone time, and two thermostats I09 and III located in the passengercompartment; adjacent the'floor thereof. Thus, three separatethermostats have been provided for controlling'the supply of overheadheat. Likewise, three separate thermostats have been provided forcontrolling the cooling apparatus.

.below 50 so as to energize the solenoid 'In the arrangement shown inFigs. 2, 3 and 4 manual switches I02, I06, I08, H0, H2 and H4 have beenprovided for selecting the particular thermostats to be used at any onetime. Reference numeral I02 designates the manual switch which is usedfor placing the 79 overhead heat thermostat in control of the solenoidI04. Reference numerals I06 and I08 designate manual switches arrangedin series with the 75 and 72 thermostats, respectively. Only one of themanual switches I02, I06 and I08 is intended to be closed at any onetimeand the particular switch which is closed depends upon what temperatureis to be maintained in the car. Manual switches IIO, II2, II4 arearranged in series with the 78, 74 and 71 cooling thermostatsrespectively. When it is desired to maintain the temperature withinthecar between 74 and 75, the manual switches H2 and I06 would be closedso as to place the 74 cooling thermostat and the 75 overhead heatthermostat in control of the cooling apparatus and the overhead heatcoil respectively. The cooling thermostats control the solenoid II6which when energized closes the switch 52 so as to cause the compressormotor 36 to operate.

should be used. It has also been found that at.

temperatures below 50 it is necessary to provide heat adjacent the floorof the passenger compartment as well as to discharge heated air into thespace above the passanger compartment. Accordingly the 50 outsidethermostat has been provided in series with the solenoid I22. The 50outside thermostat is adapted-to close whenever the outside airtemperature drops I22. Energization of the solenoid I22 opens the switchI24 which renders the refrigerating apparatus inoperative bydeenergizing the compressor control solenoid I6. Energization of thesolenoid I22 also serves to close the switch I26 which is arranged inseries with the 73 floor heat thermostat I09 and the solenoid I28.Energization of the solenoid I26 lifts the switches I38, I40, I42, andI44 so as to turn on floor heat as will be described more fullyhereinafter. Energization of the solenoid I22 also closes the switch I3Iarranged in series with the switch H8 and the 72 floor heat thermostatwhich controls the electric floor heaters through the solenoid I20 andthe switch 50. By virtue of the above described arrangement, wheneverthe outside air temperature drops below 50, the refrigerating apparatusis rendered ineffective, the 73 floor heat thermostat is placed incontrol of the solenoid I28 and the 72 floor heat thermostat is placedin control of the solenoid I20. The

72 and 73 floor heat thermostats are adapted the temperature adjacentthe floor drops below 72 the electric floor heat is .turned on. Thisserves the dual purpose of increasing the-load onheat available forheating and also serves to supplementv the engine waste heat'byelectrical heat. Energ'ization of the solenoid I28 makes it possible toutilize waste heat of the engine for heating the air adjacent the floor.

In Fig. 2 of the drawings, the thermostats are shown in the positionwhich they will occupy when the outside temperature is below 50 and theinside temperature is below 70. In, Fig. 3 shown the arrangement of thethermostats and the switches when the outside temperature is above 50and the inside temperature is between 73 and 74. The heavy line circuitsindicate those circuits which are energized, whereas the light linecircuits indicate those circuits which are deene'rgized. For purposes ofillustration the manual switches I06 and H2 have been shown closed inFigs. .3 and 4 whereby the 75 overhead heat thermostat controls thecircuit through the solenoid I04 and the 74 cooling thermostat controlsthe circuit through the relay IIB.

When the inside temperature is between 73 and 74 and the outsidetemperature is above 50 the solenoid I04 is energized through the 75overhead heat thermostat. Under these conditions the circuit iscompleted through the solenoid valve V-I whereby the valve VI is closed.The circuit through the valve V-4 is likewise closed with the resultthat the valve V4 is opened. The valves V-2 and V3 which are normallyclosed when deenergized are closed under these conditions since thecircuits leading thereto are deenergized. The solenoid I04 controls theswitches I30, I32, I34 and I36 arranged as shown in Figs. 2, 3 and 4.The solenoid I28 controls the switches I38, I40, I42 and I44, arrangedas shown in Figs; 2 through 4. Whenever the, solenoid I04 is energizedand the switches I30, I32, I34 and I36 are in their elevated positions,the overhead heat is on. Whenever the solenoid I28 is energized and theswitches I38, I40, I42 and I44 are in their elevated position the floorheat, supplied by thefloor coil I2, is on.

Fig. 4 shows in heavy lines those circuits which are energized when theoutside temperature is above 50 and the inside temperature is between 74and 75. Fig. 4 shows the 75 overhead heat thermostat in control of theoverhead heat solenoid I04 and shows the 74 cooling thermostat incontrol of the compressor motor and therefore the cooling coil I2.

As best shown in Fig. 2 in which all of the circuits are deenergized byvirtue of the manual switch IOI being open, the" solenoid valves V-2,

. V3 and V-4 are closed when deenergized the engine so as to increasethe waste engine 15 whereas the solenoid valve V--I is open whendeenergized. When it is desired to discontinue operation of the Dieselengine and to energize the compressor motor and the electric iloor heatcoils from an external source of electric energy, the jumper 46 carriedby the plug 40 closes the circuit between the contacts 48 whereby the 72floor heat thermostat controls the floor heat solenoid I20.

The circuit diagram shown in Figs. 2, 3 and 4, merely illustraterepresentative conditions. Obviously, other portions of the circuitswould be energized under other conditions. It is not considerednecessary to show those portions of the circuits which would beenergized under every conceivable combination of inside, outside andfloor temperatures.

Each .01 the solenoid operated switches shown herein is of the typewhich drops by gravity and is lifted when the switch operating solenoidis energized. In the circuits shown in Figs. 5 and 6 all of thethermostats are of the type which.

are adapted to be closed upon an increase in temperature. The overheadheat control thermo stats and the refrigeration control thermostats ineach case are adapted to be placed within the passenger compartment soas to respond to the temperature prevailing in the passengercompartment. A preferred location for these thermostats is in the returnair stream.

Figs. 5 and 6 show a modified circuit arrangement which includes fouradditional outside thermostats which are used for automaticallyselecting the temperature to be maintained within the conditioned space.The four additional outside thermostats are set to operate at 35, 70, 80and 90. The 90 outside thermostat controls the solenoid 302 which inturn controls the switch 304 in series with the 74 refrigeration controlthermostat and also controls the switch 306 arranged in series with the75 overhead heat control thermostat. The 80 outside thermostat controlsthe solenoid 308 which when energized lifts the switches 3 l0 and 3l2which are arranged in series with the 71 and 72 thermostats re-.

spectively. The 70 outside thermostat controls the solenoid-3M whichwhen energized lifts the switches SH; and 318. The switch 3l6 is inseries with the 71 refrigeration control thermostat and the switch 3l8is in series with the 72 overhead heat control thermostat. The outsidethermostats are adapted to place the proper inside thermostats incontrol of the overhead heat and the compressor motor. When the outsidetemperature is above 90, all of the outside thermostats will be closedand the 78 and 79 indoor thermostats will be the only thermostatscapable of controlling the overhead heat and the refrigeration. Theinside temperature accordingly will be maintained between 78 and 79. Ifthe outside temperature drops below 90 but remains above 80, thesolenoid 302 will allow the switches 306 and 306 to close whereby the 74and 75 indoor thermostats will control the heating and cooling so as tomaintain the inside temperature between 74 and 75. If the outsidetemperature drops to a value below 80 but above 70, the

solenoid 308 will be deenergized whereby the switches 3l0 and M2 willclose, since the outside temperature is above 70 the solenoid 314 willbe energized and the contacts 3|5 and 3l8 will be lay 30L Deenergizationof the relay 3M opens the switch 320 so as to render the 75 thermostatincapable of turning off the overhead heat. As a consequence thereof,the 79 thermostat controls the solenoid 204 whereby overhead heat willbe supplied at all temperatures below 79. Referring to Figs. 5 and 6, itwill be observed that the solenoid 204 controls the switches 230, 232,

234 and 235 respectively. In this modification,

as in the modification shown in Figs. 2, 3 and 4. the 73 floor heatthermostat controls the solenoid 228 which in turn controls theapplication of floor heat through the switches 238, 240, 242 and 244. Inthe modification shown in Figs. 5 and 6 the 72 floor heat thermostatcontrols the electric floor heaters through the solenoid 220. The 50outside thermostat controls the solenoid 222 which in turn controls theswitches 224, 226 and 23l. It will be observed that the switch 224 is inseries with a solenoid 322 which in turn controls a switch 324 so as toprevent operation of the compressor motor at temperatures below 50.

closed whereby the inside temperature will be maintained between 71 and72. As the outside temperature drops below 70, the 70 thermostat willopen so as to deenergize the solenoid 3M. Deenergization of the solenoid3|4, opens the switches 3IB and 318 whereby the 71 and 72 insidethermostats are rendered inoperative and the 74 and 75 thermostatscontrol the air conditioning apparatus. By virtue of this arrangementwhen the outside temperature is between and 70 a slightly higher indoortemperature will be maintained so as to compensate for the coldwindows,'etc. When the inside temperature drops below 50 the solenoid222 becomes deenergized with the result that switches falls below 35, itbecomes necessary to maintain considerably higher temperatures in thecar. Accordingly, the outside thermostat opens at temperatures below 35so as to deenergize the re- In order to simplify this disclosurespecific temperatures have been referred to throughout, whereas it isapparent that other temperature values may be used without departingfrom the spirit of this invention. Thus, the 50 outside thermostatcould, for example, be set to operate at or any other temperature whichmay be found more suitable.

In each instance where several thermostats have been shown in the samelocation, it is apparent that a single thermostat having several sets ofcontacts adapted to close at different temperatures could be substitutedtherefor.

While the arrangement disclosed herein is especially suitable for use onrailway cars, it is apparent that the system is also applicable tostationary installations.

While the form of embodiment of the invention as herein disclosed,constitutes a preferred form,'it is to be understood that other formsmight be adopted, all coming within the scope of the claims whichfollow.

What is claimed is as follows:

1. In combination with an enclosure, an internal combustion engine, agenerator driven by said engine, electric heaters within said enclosureadapted to be supplied with electrical energy from said generator, meansfor supplying waste heat from said engine to said enclosure includingmeans for supplying a portion of said waste heat into the upper portionof said enclosure and another portion of said heat to the lower portionof said enclosure, means responsive tothe temperature within saidenclosure controlling the heat supplied to the upper portion of saidenclosure, thermostatic means controlling the supply of waste heat tothe lower portion of said enclosure, and temperature responsive meanspreventing energization of said electrical heaters when the temperaturesin the enclosure are such that one or the other 01' said waste heatsupplying means is inoperative to supply waste heat to said enclosure.

2. Means for heating an enclosure comprising in combination, an internalcombustion engine, means for supplying waste heat from said engine tosaid enclosure, a generator driven by said engine, electric heatingmeans, means for energizing said electric heating means from saidgenerator so as to heat air for said enclosure, means responsive to thetemperature in said enclosure controlling said electric heating means,control means responsive to the temperature outside source of electricenergyfor energizing said electric heating means, and means forautomatically rendering said outside temperature control meansinoperative upon connection of said electric heating means to saidoutside source of electric energy.

3. Air conditioning apparatus for use in conditioning an enclosurecomprising in combination, an internal combustion enginefor supplyingpower, a generator driven by said engine,

means utilizing waste heat of said engine for heating air for saidenclosure including means located above the normal head-room of saidenclosure for supplying heat to the upper portion of said enclosure andmeans located below the normal head room of said enclosure for supplyingheat to the lower portion of saidlenclosure, means responsive to thetemperature within said enclosure controlling the application of heatin" the upper portion of said enclosure and means responsive to thetemperature within said enclosure for controlling the application ofheat to the lower portion of said enclosure, means responsive to theoutside air temperature preventing the application of heat to the lowerportion of said enclosure within a predetermined outside temperaturerange within which some form of heating is required, electric heatersenergized from said generator for heating air for said enclosure onlywhen said waste heat is insuflicient for heating said enclosure, andmeans responsive to the outside temperature controlling said electricheaters.

4," In combination with an enclosure, an internal combustion engine, agenerator driven by said engine, electric heaters for heating air forsaid enclosure, means for supplying electrical energy from saidgenerator to said electric heaters, coil means for heating air for saidenclosure, means for transferring waste heat generated by said internalcombustion engine to said coil means, means for cooling air for saidenclosure,

means for flowing said cooled air in thermal exchange with said collmeans, means responsive to the temperature in said enclosure controllingsaid coil means, and means responsive to the temperature outside saidenclosure preventing ,operation of said electric heaters when theoutside temperature is above a predetermined value.

5. In combination,-means for heating an enclosure including means forsupplying heat to the upper portion of the enclosure and a second meansfor supplying heat adjacent the floor of the enclosure and control meansfor said first and second named'means comprising thermostatie meansresponsive to the temperature in the upper portion of said enclosurecontrolling the application of heat to the upper portion of saidenclosure, thermostaticmeans responsive to the temperature in th lowerportion of said enclosure controlling the application of heat adjacentthe floor of said enclosure, and means responsive to the outsidetemperature iorturning oil the supply of heat adjacent the floor and forchanging the control point of the temperature responsive means in theupper-portion of said enclosure as the outside temperature increasesabove a predetermined value.

6. In combination, first means for heating the air in the upper portionof an enclosure, second means for heating the air in the lower portionof said enclosure, third means for heating air in the lower portion ofsaid enclosure, means responsive to the temperature within saidenclosure for controlling the heat supplied to the upper portion of saidenclosure, means responsive to the temperature outside said enclosurepreventing operation of the second named means for supplying heat whenthe outside temperature is above a predetermined value, and meanspreventing heating by said third named means until after said first andsecond means have been called on to supply heat.

DONALD F. ALEXANDER. JAMES R. HORNADAY. ALBERT J. 'KUHN.

